American Apparel began to lay off 2,400 workers in Southern California on Monday — kicking off its final chapter as the country’s largest garment maker.

Layoffs will continue through the rest of the week and affect workers on the manufacturing and production side, American Apparel said. The company has about 3,500 factory workers in the Southland.

Canadian clothing maker Gildan Activewear won an auction in bankruptcy court last week to buy the American Apparel brand and some manufacturing equipment for $88 million. The company will not assume American Apparel’s leases on its factories.

Until the sale closes in February, some workers are being kept on to operate the factories in downtown Los Angeles and in Garden Grove, as well as the distribution center in La Mirada. Some will also continue working in human resources and other departments to keep the company running. American Apparel’s 110 stores and its website will remain open, until at least April, under a 100-day license with Gildan.

On Monday, workers at the company’s headquarters in downtown Los Angeles said they were shocked even though they had been warned in December there might be mass layoffs. Many said they had hoped Gildan or another company would come in and save jobs.

Francesca Cortes, a seamstress who works on the overnight shift, said she was told to come into work on Monday for a possible shift change. Instead of a new schedule, she got her final paycheck and a termination letter.